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24 The Respiratory System PowerPoint® Lecture Presentations prepared by Steven Bassett Southeast Community College Lincoln, Nebraska © 2012 Pearson Education, Inc. Introduction • The respiratory system includes: • • • • • • • • • Nose Nasal cavity Sinuses Pharynx Larynx Trachea Bronchi Bronchioles Alveoli © 2012 Pearson Education, Inc. An Overview of the Respiratory System •The upper respiratory system •Consists of: •Nose, nasal cavity, sinuses, and pharynx •The lower respiratory system •Consists of: •Larynx, trachea, bronchi, bronchioles, and alveoli © 2012 Pearson Education, Inc. Figure 24.1 Structures of the Respiratory System Frontal sinus Nasal cavity Nasal conchae Nose Sphenoidal sinus Internal nares Tongue Nasopharynx UPPER RESPIRATORY SYSTEM LOWER RESPIRATORY SYSTEM Hyoid bone Larynx Esophagus Trachea Bronchus Clavicle Bronchioles RIGHT LUNG Ribs © 2012 Pearson Education, Inc. LEFT LUNG Diaphragm An Overview of the Respiratory System • Functions of the Respiratory System • The following is a partial list of respiratory functions • Provides an area for gas exchange between the air and the blood • Protects the respiratory surfaces from dehydration (for example) • Provides protection against invading pathogens • Produces sound involved in verbal communication • Assists in the regulation of blood volume, blood pressure, and body fluid pH © 2012 Pearson Education, Inc. An Overview of the Respiratory System • The Respiratory Epithelium • Consists of: • Pseudostratified, ciliated, columnar cells (except for the pharynx, smaller bronchi, and alveoli) • Mucus-producing cells • Pharynx consists of stratified squamous cells © 2012 Pearson Education, Inc. An Overview of the Respiratory System • The Respiratory Epithelium • Function • Ciliated columnar cells move mucus in an upward manner (mucus escalator) so debris can be coughed out • Mucous cells produce mucus so inhaled debris will get stuck and not enter the lungs • Stratified squamous cells provide protection against abrasion © 2012 Pearson Education, Inc. An Overview of the Respiratory System • Protection of the Respiratory System • Hairs in the nose block some of the inhaled debris • Called vibrissae • Nasal cavity produces mucus to trap inhaled debris • Sneezing will remove this debris • Respiratory epithelium mucus will trap inhaled debris • Coughing will remove this debris © 2012 Pearson Education, Inc. The Upper Respiratory System • The following is the pathway of air: • Air enters the external nares • Passes by the nasal vestibule • Area surrounded by the two pairs of alar cartilage • Enters the nasal cavity • Air flows in and around the nasal conchae • Inferior, middle, and superior conchae • As air swirls around the conchae, debris gets stuck in the mucus • As air swirls around the conchae, the air warms a bit before entering the trachea © 2012 Pearson Education, Inc. The Upper Respiratory System • The following is the pathway of air (continued): • Air enters the internal nares • Air enters the nasopharynx area © 2012 Pearson Education, Inc. Figure 24.4a Respiratory Structures in the Head and Neck, Part II Frontal sinus Nasal cavity Superior Middle Internal nares Inferior Nasal conchae Nasopharynx Nasal vestibule Pharyngeal tonsil External nares Entrance to auditory tube Hard palate Soft palate Palatine tonsil Oral cavity Oropharynx Tongue Epiglottis Mandible Aryepiglottic fold Lingual tonsil Hyoid bone Laryngopharynx Thyroid cartilage Glottis Cricoid cartilage Vocal fold Trachea Esophagus Thyroid gland A sagittal section of the head and neck © 2012 Pearson Education, Inc. The Upper Respiratory System • The Pharynx • The pharynx is a passageway that connects the nose to the mouth to the throat • Nasopharynx (the back of the nose area) • Oropharynx (the back of the mouth area) • Laryngopharynx (the area that has the entrance to the trachea and esophagus) © 2012 Pearson Education, Inc. Figure 24.4a Respiratory Structures in the Head and Neck, Part II Frontal sinus Nasal cavity Superior Middle Internal nares Inferior Nasal conchae Nasopharynx Nasal vestibule Pharyngeal tonsil External nares Entrance to auditory tube Hard palate Soft palate Palatine tonsil Oral cavity Oropharynx Tongue Epiglottis Mandible Aryepiglottic fold Lingual tonsil Hyoid bone Laryngopharynx Thyroid cartilage Glottis Cricoid cartilage Vocal fold Trachea Esophagus Thyroid gland A sagittal section of the head and neck © 2012 Pearson Education, Inc. The Lower Respiratory System • The Larynx • A cylinder whose cartilaginous walls are stabilized by ligaments or skeletal muscles or both • Begins at the level of vertebrae C4 or C5 • Ends at the level of vertebra C7 © 2012 Pearson Education, Inc. The Lower Respiratory System • Cartilages of the Larynx • Thyroid cartilage • Contains the laryngeal prominence • Cricoid cartilage • Epiglottis • Closes over the glottis during swallowing of food • Paired laryngeal cartilages • Some play a role in the opening and closing of the glottis © 2012 Pearson Education, Inc. Figure 24.4a Respiratory Structures in the Head and Neck, Part II Frontal sinus Nasal cavity Superior Middle Internal nares Inferior Nasal conchae Nasopharynx Nasal vestibule Pharyngeal tonsil External nares Entrance to auditory tube Hard palate Soft palate Palatine tonsil Oral cavity Oropharynx Tongue Epiglottis Mandible Aryepiglottic fold Lingual tonsil Hyoid bone Laryngopharynx Thyroid cartilage Glottis Cricoid cartilage Vocal fold Trachea Esophagus Thyroid gland A sagittal section of the head and neck © 2012 Pearson Education, Inc. Figure 24.6a Anatomy of the Larynx Epiglottis Lesser cornu Hyoid bone Thyrohyoid ligament (extrinsic) Thyroid cartilage Larynx Laryngeal prominence Cricothyroid ligament (intrinsic) Cricoid cartilage Cricotracheal ligament (extrinsic) Trachea Tracheal cartilages Anterior view of the intact larynx © 2012 Pearson Education, Inc. Figure 24.6b Anatomy of the Larynx Epiglottis Vestibular ligament Vocal ligament Thyroid cartilage Arytenoid cartilage Cricoid cartilage Tracheal cartilages Posterior view of the intact larynx © 2012 Pearson Education, Inc. The Lower Respiratory System • Laryngeal Ligaments • A series of intrinsic laryngeal ligaments bind the laryngeal cartilages together • Extrinsic laryngeal ligaments bind the thyroid cartilage to the hyoid bone and cricoid cartilage • Some of the ligaments become the vocal cords © 2012 Pearson Education, Inc. The Lower Respiratory System • Sound Production by the Vocal Cords • Air passing between the vocal cords creates sound • Pitch depends on the diameter, length, and tension in the vocal cords • Children have slender, short vocal folds thus creating a high-pitched sound • At puberty, the vocal cords of males become thicker and longer thus producing a deeper voice than females • Amplification of sound occurs in the sinus cavities • Production of definite sounds depends on movement of the lips, tongue, and cheeks © 2012 Pearson Education, Inc. Figure 24.7ab The Vocal Cords Corniculate cartilage POSTERIOR Corniculate cartilage Glottis (closed) Cuneiform cartilage Glottis (open) Aryepiglottic fold Vestibular fold Vocal fold Vocal fold Vestibular fold Epiglottis Epiglottis Root of tongue ANTERIOR Glottis in the open position © 2012 Pearson Education, Inc. Glottis in the closed position Figure 24.7bc The Vocal Cords POSTERIOR POSTERIOR Corniculate cartilage Glottis (closed) Glottis (open) Cuneiform cartilage in aryepiglottic fold Vocal fold Vestibular fold Epiglottis ANTERIOR Root of tongue Glottis in the closed position ANTERIOR This photograph is a representative laryngoscopic view. For this view the camera is positioned within the oropharynx, just superior to the larynx. © 2012 Pearson Education, Inc. The Lower Respiratory System • Laryngeal Musculature • Intrinsic muscles • Regulate tension of the vocal cords • Open and close the glottis • Extrinsic muscles • Position and stabilize the larynx © 2012 Pearson Education, Inc. Figure 24.8 Movements of the Larynx during Swallowing Tongue forces compacted bolus into oropharynx. Hard palate Soft palate Tongue Bolus Epiglottis Larynx Trachea Laryngeal movement folds epiglottis; pharyngeal muscles push bolus into esophagus. Soft palate Bolus Epiglottis Bolus moves along esophagus; larynx returns to normal position. Epiglottis Bolus Trachea © 2012 Pearson Education, Inc. The Trachea • Characteristics of the Trachea • About 2.5 cm in diameter • Contains tracheal cartilage • Each cartilage ring is actually C-shaped, not a complete ring • Connecting one cartilage ring to another are annular ligaments • The lining consists of: • Respiratory epithelia • Lamina propria • Submucosa © 2012 Pearson Education, Inc. Figure 24.9a Anatomy of the Trachea and Primary Bronchi Hyoid bone Larynx Annular ligaments Trachea Tracheal cartilages Location of carina (internal ridge) Root of right lung Root of left lung Superior lobar bronchus Lung tissue Primary bronchi Superior lobar bronchus Secondary bronchi Middle lobar bronchus Inferior lobar bronchi RIGHT LUNG LEFT LUNG Anterior view showing the plane of section for part (b) © 2012 Pearson Education, Inc. The Trachea • Characteristics of the Trachea (continued) • The posterior side of the cartilage ring is the trachealis muscle • This muscle allows for constriction and dilation of the trachea • The trachea branches at the carina to form the left and right bronchi © 2012 Pearson Education, Inc. Figure 24.9a Anatomy of the Trachea and Primary Bronchi Hyoid bone Larynx Annular ligaments Trachea Tracheal cartilages Location of carina (internal ridge) Root of right lung Root of left lung Superior lobar bronchus Lung tissue Primary bronchi Superior lobar bronchus Secondary bronchi Middle lobar bronchus Inferior lobar bronchi RIGHT LUNG LEFT LUNG Anterior view showing the plane of section for part (b) © 2012 Pearson Education, Inc. Figure 24.9b Anatomy of the Trachea and Primary Bronchi Esophagus Trachealis muscle Lumen of trachea Thyroid gland Respiratory epithelium Tracheal cartilage The trachea Histological cross-sectional view of the trachea showing its relationship to surrounding structures © 2012 Pearson Education, Inc. LM 3 The Primary Bronchi • The left and right primary bronchi branch off the trachea at the area of the carina • The primary bronchi enter into each lung • The right primary bronchus is steeper and larger in diameter than the left • Hence, children can aspirate foreign objects into the right lung easier than the left lung © 2012 Pearson Education, Inc. The Primary Bronchi • Each primary bronchus will enter the lung at the point called the hilum • The hilum is also the point of entrance and exit of the pulmonary blood vessels • The combination of the bronchus, artery, and vein is called the root © 2012 Pearson Education, Inc. Figure 24.1 Structures of the Respiratory System Frontal sinus Nasal cavity Nasal conchae Nose Sphenoidal sinus Internal nares Tongue Nasopharynx UPPER RESPIRATORY SYSTEM LOWER RESPIRATORY SYSTEM Hyoid bone Larynx Esophagus Trachea Bronchus Clavicle Bronchioles RIGHT LUNG Ribs © 2012 Pearson Education, Inc. LEFT LUNG Diaphragm The Lungs • Structure of the Lungs • The apex points superiorly and the base inferiorly • The right lung has three lobes • Superior, middle, and inferior lobes • Consists of a horizontal fissure and an oblique fissure • The left lung has two lobes • Superior and inferior lobes • Contains the oblique fissure • Left lung has a cardiac notch © 2012 Pearson Education, Inc. Figure 24.10ab Superficial Anatomy of the Lungs Boundary between right and left pleural cavities Superior lobe LEFT LUNG RIGHT LUNG Superior lobe Oblique fissure Horizontal fissure Middle lobe Fibrous layer of pericardium Oblique fissure Inferior lobe Inferior lobe Falciform ligament Anterior view of the opened chest, showing the relative positions of the left and right lungs and heart. Liver, right lobe Cut edge of diaphragm Liver, left lobe Lateral Surfaces Diagrammatic views of the lateral surfaces of the isolated right and left lungs Apex Apex Superior lobe Superior lobe Horizontal fissure Middle lobe Cardiac notch Inferior lobe Oblique fissure Base RIGHT LUNG © 2012 Pearson Education, Inc. Oblique fissure Inferior lobe Base LEFT LUNG Figure 24.10c Superficial Anatomy of the Lungs Medial Surfaces Apex Diagrammatic views of the medial surfaces of the isolated right and left lungs Superior lobe Superior lobar bronchus Superior lobe Pulmonary arteries Middle lobar bronchus Groove for aorta Superior lobar bronchus Pulmonary veins Horizontal fissure Oblique fissure Inferior lobar bronchus Middle lobe Cardiac impression Hilum Inferior lobe Groove for esophagus Inferior lobe Oblique fissure Diaphragmatic surface Base RIGHT LUNG © 2012 Pearson Education, Inc. Pulmonary veins LEFT LUNG The Lungs • Structure of the Pulmonary Bronchi • The primary bronchi branch numerous times once inside the lungs (outside the lungs they are called extrapulmonary bronchi while inside the lungs they are called intrapulmonary bronchi) • Each primary bronchus divides to form: • Secondary bronchi and tertiary bronchi • Each tertiary bronchus goes to a specific lung area called a bronchopulmonary segment © 2012 Pearson Education, Inc. The Lungs • Detailed Branching of the Primary Bronchi • The right lung has 10 tertiary bronchi and therefore 10 bronchopulmonary segments • The left lung has 8 or 9 segments • The trachea and primary bronchi have rings of cartilage • The secondary and tertiary have cartilage plates • The final branch (bronchiole) does not have any cartilage © 2012 Pearson Education, Inc. Figure 24.12b The Bronchial Tree and Divisions of the Lungs Apicoposterior Apical Bronchopulmonary segments of superior lobe Posterior Anterior Anterior Superior lingular Inferior lingular Medial Bronchopulmonary segments of middle lobe Bronchopulmonary segments of superior lobe Lateral Superior Superior Medial basal Bronchopulmonary segments of inferior lobe Lateral basal Posterior basal Medial basal Anterior basal Posterior basal Lateral basal Anterior basal Right lung, costal surface Left lung, costal surface Isolated left and right lungs have been colored to show the distribution of the bronchopulmonary segments. © 2012 Pearson Education, Inc. Bronchopulmonary segments of inferior lobe Figure 24.11 Bronchi and Bronchioles LEFT LUNG Primary bronchus Cartilage ring Secondary (superior lobar) bronchus Root of lung Secondary (inferior lobar) bronchus Cartilage plates Visceral pleura Tertiary bronchi BRONCHIOLE Respiratory epithelium Smooth muscle Bronchioles Lobule © 2012 Pearson Education, Inc. Respiratory bronchioles Terminal bronchiole The Lungs • The Bronchioles • Tertiary bronchi give rise to bronchioles • Bronchioles have a diameter of 0.3–0.5 mm • They are self-supporting and therefore do not require cartilage plates • Consist of smooth muscle for bronchodilation (sympathetic stimulation) and bronchoconstriction (parasympathetic stimulation) • Bronchioles terminate with clusters of alveolar sacs © 2012 Pearson Education, Inc. Figure 24.13a Bronchi and Bronchioles Trachea Respiratory epithelium Bronchiole Bronchial artery (red), vein (blue), and nerve (yellow) Left primary bronchus Visceral pleura Branch of pulmonary artery Smooth muscle around terminal bronchiole Terminal bronchiole Secondary bronchus Tertiary bronchi Respiratory bronchiole Elastic fibers Smaller bronchi Bronchioles Branch of pulmonary vein Capillary beds Terminal bronchiole Respiratory bronchiole Arteriole Lymphatic vessel Alveolar duct Alveoli Alveoli in a pulmonary lobule Bronchopulmonary segment Alveolar sac Interlobular septum Visceral pleura Pleural cavity Parietal pleura The structure of one portion of a single pulmonary lobule © 2012 Pearson Education, Inc. The Lungs • Alveolar Ducts and Alveoli • Each lung has about 150 million alveoli • Extensive network of capillaries surround each alveolus • Capillaries drop off carbon dioxide and pick up oxygen • Elastic tissue surrounds each alveolus • Maintains the shape and position of each alveolus during inhalation and exhalation © 2012 Pearson Education, Inc. Figure 24.14a Alveolar Organization Respiratory bronchiole Smooth muscle Alveolar duct Alveolus Elastic fibers Alveolar sac Capillaries Basic structure of a lobule, cut to reveal the arrangement between the alveolar ducts and alveoli. A network of capillaries surrounds each alveolus. These capillaries are surrounded by elastic fibers. © 2012 Pearson Education, Inc. The Lungs • Alveoli Details • The cells associated with alveoli • The lining consists of a single layer of squamous cells • These are called type I pneumocytes • Type II pneumocytes are scattered among the type I pneumocytes • Type II pneumocytes secrete surfactant • Surfactant prevents alveolar collapse • Alveolar macrophages wander around phagocytizing particulate matter © 2012 Pearson Education, Inc. Figure 24.14bc Alveolar Organization Alveoli Alveolar sac Alveolar duct Lung tissue LM 125 SEM of lung tissue showing the appearance and organization of the alveoli Pneumocyte type II cell Pneumocyte type I cell Alveolar macrophage Elastic fibers Alveolar macrophage Capillary Endothelial cell of capillary Diagrammatic sectional view of alveolar structure and the respiratory membrane © 2012 Pearson Education, Inc. The Lungs • Gas Exchange at the Alveoli • Pulmonary arteries transport carbon dioxide to the alveolar capillaries • Carbon dioxide leaves the capillaries and enters the alveolar sacs • Oxygen leaves the alveolar sacs and enters the capillaries • Oxygen enters the pulmonary veins and returns to the heart to be pumped to all parts of the body © 2012 Pearson Education, Inc. Figure 24.14cd Alveolar Organization Pneumocyte type II cell Pneumocyte type I cell Alveolar macrophage Red blood cell Elastic fibers Capillary lumen Nucleus of endothelial cell Endothelium Alveolar macrophage 0.5 m Capillary Endothelial cell of capillary Diagrammatic sectional view of alveolar structure and the respiratory membrane © 2012 Pearson Education, Inc. Fused Alveolar Surfactant basal epithelium laminae Alveolar air space The respiratory membrane Figure 24.13a Bronchi and Bronchioles Trachea Respiratory epithelium Bronchiole Bronchial artery (red), vein (blue), and nerve (yellow) Left primary bronchus Visceral pleura Branch of pulmonary artery Smooth muscle around terminal bronchiole Terminal bronchiole Secondary bronchus Tertiary bronchi Respiratory bronchiole Elastic fibers Smaller bronchi Bronchioles Branch of pulmonary vein Capillary beds Terminal bronchiole Respiratory bronchiole Arteriole Lymphatic vessel Alveolar duct Alveoli Alveoli in a pulmonary lobule Bronchopulmonary segment Alveolar sac Interlobular septum Visceral pleura Pleural cavity Parietal pleura The structure of one portion of a single pulmonary lobule © 2012 Pearson Education, Inc. The Pleural Cavities and Pleural Membranes • The right and left pleural cavities are separated by the mediastinum • Each lung is lined by a serous membrane • The membrane is made of two continuous layers • Visceral pleura portion covers the outer surface of the lung • Parietal pleura portion covers the inside lining of the thoracic wall • The space created between the visceral and parietal is the pleural cavity © 2012 Pearson Education, Inc. The Pleural Cavities and Pleural Membranes • The pleural cavity between the visceral and parietal membranes consists of: • Pleural fluid • Reduces friction when the lungs move upon inhalation and exhalation • Pleurisy • A condition in which the membranes produce too much pleural fluid or the membranes adhere to the thoracic wall thereby resulting in pain upon inhalation and exhalation © 2012 Pearson Education, Inc. Figure 24.15 Anatomical Relationships in the Thoracic Cavity Pericardial cavity Body of sternum Right lung, middle lobe Ventricles Oblique fissure Right pleural cavity Rib Left lung, superior lobe Visceral pleura Atria Esophagus Aorta Right lung, inferior lobe Left pleural cavity Parietal pleura Bronchi Left lung, inferior lobe Spinal cord Posterior mediastinum © 2012 Pearson Education, Inc. Respiratory Muscles and Pulmonary Ventilation • Respiratory Muscles • The muscles involved in pulmonary ventilation (breathing) are: • Diaphragm • External intercostals • Internal intercostals © 2012 Pearson Education, Inc. Respiratory Muscles and Pulmonary Ventilation • Diaphragm • Contracts (lowers) to cause inhalation • Relaxes (raises) to cause exhalation • External intercostals • Elevate the ribs to aid in inhalation • Internal intercostals • Depress the ribs to aid in exhalation © 2012 Pearson Education, Inc. Figure 24.16a Respiratory Muscles Ribs and sternum elevate Diaphragm contracts As the ribs are elevated or the diaphragm is depressed, the volume of the thoracic cavity increases and air moves into the lungs. The outward movement of the ribs as they are elevated resembles the outward swing of a raised bucket handle. © 2012 Pearson Education, Inc. Figure 24.16b Respiratory Muscles Accessory Muscles of Inspiration External intercostal muscles Sternocleidomastoid muscle Scalene muscles Accessory Muscles of Exhalation Internal intercostal muscles Pectoralis minor muscle Transversus thoracis muscle Serratus anterior muscle External oblique muscle Diaphragm Rectus abdominus Internal oblique muscle The primary and accessory muscles of respiration © 2012 Pearson Education, Inc. Figure 24.16c Respiratory Muscles Scalene muscles Sternocleidomastoid muscle Pectoralis minor muscle Serratus anterior muscle External intercostal muscles Diaphragm Inhalation, showing the primary and accessory respiratory muscles that elevate the ribs and flatten the diaphragm. © 2012 Pearson Education, Inc. Figure 24.16d Respiratory Muscles Transversus thoracis muscle Internal intercostal muscles Rectus abdominis and other abdominal muscles (not shown) Exhalation, showing the primary and accessory respiratory muscles that depress the ribs and elevate the diaphragm. © 2012 Pearson Education, Inc. Respiratory Muscles and Pulmonary Ventilation • Respiratory Movements • Respiratory movements can be classified two ways: eupnea or hyperpnea • Eupnea: quiet breathing • May involve diaphragmatic breathing or costal breathing or both • During pregnancy, due to the uterus pushing upward on the diaphragm, women typically use costal breathing • Hyperpnea: forced breathing • Generally requires the use of accessory breathing muscles © 2012 Pearson Education, Inc. Figure 24.16b Respiratory Muscles Accessory Muscles of Inspiration External intercostal muscles Sternocleidomastoid muscle Scalene muscles Accessory Muscles of Exhalation Internal intercostal muscles Pectoralis minor muscle Transversus thoracis muscle Serratus anterior muscle External oblique muscle Diaphragm Rectus abdominus Internal oblique muscle The primary and accessory muscles of respiration © 2012 Pearson Education, Inc. Respiratory Muscles and Pulmonary Ventilation • Respiratory Centers of the Brain • There are three pairs of nuclei in the pons and medulla oblongata that regulate the respiratory muscles • The respiratory rhythmicity center sets the respiratory pace • The apneustic center adjusts the respiratory pace • The pneumotaxic center adjusts the respiratory pace © 2012 Pearson Education, Inc. Figure 24.17 Respiratory Centers and Reflex Controls Cerebrum HIGHER CENTERS Cerebral cortex Limbic system Hypothalamus Pons Pneumotaxic center CSF CHEMORECEPTORS Apneustic center Medulla oblongata N IX and N X Chemoreceptors and baroreceptors of carotid and aortic sinuses NX Dorsal respiratory group (DRG) Stretch receptors of lungs Diaphragm Spinal cord Ventral respiratory group (VRG) Respiratory rhythmicity centers Motor neurons controlling diaphragm Motor neurons controlling other respiratory muscles KEY Phrenic nerve Stimulation Inhibition © 2012 Pearson Education, Inc. Respiratory Muscles and Pulmonary Ventilation • There are three different reflexes involved in respiration: • Mechanoreceptor reflexes • Respond to changes in lung volume or changes in blood pressure • Chemoreceptor reflexes • Respond to changes in partial pressures of carbon dioxide and oxygen • Respond to changes in pH • Protective reflexes • Respond to physical injury or irritation © 2012 Pearson Education, Inc. Aging and the Respiratory System • The respiratory system becomes less efficient as we age. • Noteworthy changes include: • Elastic tissue begins to deteriorate • Lungs cannot expand or constrict as much as they used to • Movements of the ribs are restricted due to arthritis • Some degree of emphysema, which hinders breathing • With age, roughly one square foot of respiratory membrane is lost each year after age 30 © 2012 Pearson Education, Inc.
